SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '206e3160221b7b069c26b056c83c5c23e65e1882a37bb306db52b207ecfff1a6' 
  AND token = '1r2SVeOSmXSNaOVBI1ybOAyTx42Ij3uD9lZNDBAS+Js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}